Hotfix supervisor infinite log recursion if no LogMonitor

Console

.pylintrc

@@ -2,4 +2,4 @@
 
 ignored-modules = zmq
 max-line-length = 150
-disable = missing-docstring, too-few-public-methods
+disable = missing-docstring, too-few-public-methods, invalid-name

Dockerfile

@@ -50,7 +50,7 @@ COPY nginx/default.conf ${TFW_NGINX_DEFAULT}
 COPY nginx/components/ ${TFW_NGINX_COMPONENTS}
 COPY lib LICENSE ${TFW_LIB_DIR}
 
-RUN for dir in "${TFW_LIB_DIR}"/{tfw,tao,envvars.py} "/etc/nginx" "/etc/supervisor"; do \
+RUN for dir in "${TFW_LIB_DIR}"/{tfw,tao,envvars} "/etc/nginx" "/etc/supervisor"; do \
         chown -R root:root "$dir" && chmod -R 700 "$dir";                               \
     done
 

lib/tfw/components/__init__.py

@@ -7,3 +7,4 @@ from .terminal_event_handler import TerminalEventHandler
 from .ide_event_handler import IdeEventHandler
 from .history_monitor import HistoryMonitor, BashMonitor, GDBMonitor
 from .terminal_commands import TerminalCommands
+from .log_monitoring_event_handler import LogMonitoringEventHandler

lib/tfw/components/directory_monitor.py

@@ -15,10 +15,12 @@ LOG = logging.getLogger(__name__)
 
 
 class DirectoryMonitor(ObserverMixin):
-    def __init__(self, directory):
+    def __init__(self, directories):
         ObserverMixin.__init__(self)
         self.eventhandler = IdeReloadWatchdogEventHandler()
+        for directory in directories:
             self.observer.schedule(self.eventhandler, directory, recursive=True)
+
         self.pause, self.resume = self.eventhandler.pause, self.eventhandler.resume
 
     @property

lib/tfw/components/ide_event_handler.py

@@ -98,17 +98,24 @@ class IdeEventHandler(EventHandlerBase, MonitorManagerMixin):
     By default all files in the directory specified in __init__ are displayed
     on the fontend. Note that this is a stateful component.
 
+    When any file in the selected directory changes they are automatically refreshed
+    on the frontend (this is done by listening to inotify events).
+
     This EventHandler accepts messages that have a data["command"] key specifying
     a command to be executed.
     The API of each command is documented in their respective handlers.
     """
-    def __init__(self, key, directory, allowed_directories, selected_file=None, exclude=None):
+    def __init__(self, key, directory, allowed_directories, selected_file=None, exclude=None,
+                 additional_watched_directories=None):
         """
         :param key: the key this instance should listen to
         :param directory: working directory which the EventHandler should serve files from
         :param allowed_directories: list of directories that can be switched to using the selectdir command
         :param selected_file: file that is selected by default
         :param exclude: list of filenames that should not appear between files (for *.o, *.pyc, etc.)
+        :param additional_watched_directories: refresh the selected file when files change in these directories
+                                               (the working directory is watched by default, this is useful for
+                                               symlinks and such)
         """
         super().__init__(key)
         try:
@@ -116,7 +123,11 @@ class IdeEventHandler(EventHandlerBase, MonitorManagerMixin):
                                            selected_file=selected_file, exclude=exclude)
         except IndexError:
             raise EnvironmentError(f'No file(s) in IdeEventHandler working_directory "{directory}"!')
-        MonitorManagerMixin.__init__(self, DirectoryMonitor, self.filemanager.workdir)
+
+        self.watched_directories = [self.filemanager.workdir]
+        if additional_watched_directories:
+            self.watched_directories.extend(additional_watched_directories)
+        MonitorManagerMixin.__init__(self, DirectoryMonitor, self.watched_directories)
 
         self.commands = {'read':      self.read,
                          'write':     self.write,

lib/tfw/components/log_monitor.py

@@ -0,0 +1,52 @@
+# Copyright (C) 2018 Avatao.com Innovative Learning Kft.
+# All Rights Reserved. See LICENSE file for details.
+
+import logging
+from os.path import dirname
+
+from watchdog.events import PatternMatchingEventHandler as PatternMatchingWatchdogEventHandler
+
+from tfw.networking.event_handlers import ServerUplinkConnector
+from tfw.decorators import RateLimiter
+from tfw.mixins import ObserverMixin, SupervisorLogMixin
+
+
+class LogMonitor(ObserverMixin):
+    def __init__(self, process_name, log_tail=0):
+        self.prevent_log_recursion()
+        ObserverMixin.__init__(self)
+        event_handler = SendLogWatchdogEventHandler(process_name, log_tail=log_tail)
+        self.observer.schedule(
+            event_handler,
+            event_handler.path
+        )
+
+    @staticmethod
+    def prevent_log_recursion():
+        # This is done to prevent inotify event logs triggering themselves (infinite log recursion)
+        logging.getLogger('watchdog.observers.inotify_buffer').propagate = False
+
+
+class SendLogWatchdogEventHandler(PatternMatchingWatchdogEventHandler, SupervisorLogMixin):
+    def __init__(self, process_name, log_tail=0):
+        self.acquire_own_supervisor_instance()  # This thread-localises the xmlrpc client
+        self.process_name = process_name
+        self.procinfo = self.supervisor.getProcessInfo(self.process_name)
+        super().__init__([self.procinfo['stdout_logfile'], self.procinfo['stderr_logfile']])
+        self.uplink = ServerUplinkConnector()
+        self.log_tail = log_tail
+
+    @property
+    def path(self):
+        return dirname(self.procinfo['stdout_logfile'])
+
+    @RateLimiter(rate_per_second=5)
+    def on_modified(self, event):
+        self.uplink.send({
+            'key': 'processlog',
+            'data': {
+                'command': 'new_log',
+                'stdout': self.read_stdout(self.process_name, tail=self.log_tail),
+                'stderr': self.read_stderr(self.process_name, tail=self.log_tail)
+            }
+        })

lib/tfw/components/log_monitoring_event_handler.py

@@ -0,0 +1,37 @@
+# Copyright (C) 2018 Avatao.com Innovative Learning Kft.
+# All Rights Reserved. See LICENSE file for details.
+
+
+from tfw import EventHandlerBase
+from tfw.mixins import MonitorManagerMixin
+from tfw.config.logs import logging
+from .log_monitor import LogMonitor
+
+LOG = logging.getLogger(__name__)
+
+
+class LogMonitoringEventHandler(EventHandlerBase, MonitorManagerMixin):
+    def __init__(self, key, process_name, log_tail=0):
+        super().__init__(key)
+        self.process_name = process_name
+        self.log_tail = log_tail
+        MonitorManagerMixin.__init__(self, LogMonitor, self.process_name, self.log_tail)
+
+        self.command_handlers = {
+            'process_name': self.handle_process_name,
+            'log_tail':     self.handle_log_tail
+        }
+
+    def handle_event(self, message):
+        try:
+            data = message['data']
+            self.command_handlers[data['command']](data)
+            self.reload_monitor()
+        except KeyError:
+            LOG.error('IGNORING MESSAGE: Invalid message received: %s', message)
+
+    def handle_process_name(self, data):
+        self.set_monitor_args(data['process_name'], self.log_tail)
+
+    def handle_log_tail(self, data):
+        self.set_monitor_args(self.process_name, data['log_tail'])

lib/tfw/components/process_managing_event_handler.py

@@ -4,19 +4,18 @@
 from xmlrpc.client import Fault as SupervisorFault
 
 from tfw import EventHandlerBase
-from tfw.mixins import SupervisorMixin
+from tfw.mixins import SupervisorMixin, SupervisorLogMixin
 from tfw.config.logs import logging
 from .directory_monitor import with_monitor_paused
 
 LOG = logging.getLogger(__name__)
 
 
-class ProcessManager(SupervisorMixin):
+class ProcessManager(SupervisorMixin, SupervisorLogMixin):
     def __init__(self):
         self.commands = {'start':      self.start_process,
                          'stop':       self.stop_process,
-                         'restart': self.restart_process,
-                         'readlog': self.read_log}
+                         'restart':    self.restart_process}
 
     def __call__(self, command, process_name):
         return self.commands[command](process_name)
@@ -35,21 +34,24 @@ class ProcessManagingEventHandler(EventHandlerBase):
     Commands available: start, stop, restart, readlog
     (the names are as self-documenting as it gets)
     """
-    def __init__(self, key, dirmonitor=None):
+    def __init__(self, key, dirmonitor=None, log_tail=0):
         super().__init__(key)
         self.key = key
         self.monitor = dirmonitor
         self.processmanager = ProcessManager()
+        self.log_tail = log_tail
 
     @with_monitor_paused
     def handle_event(self, message):
         try:
             data = message['data']
+            try:
                 self.processmanager(data['command'], data['process_name'])
+            except SupervisorFault as fault:
+                message['data']['error'] = fault.faultString
+            finally:
+                message['data']['stdout'] = self.processmanager.read_stdout(data['process_name'], self.log_tail)
+                message['data']['stderr'] = self.processmanager.read_stderr(data['process_name'], self.log_tail)
             return message
         except KeyError:
             LOG.error('IGNORING MESSAGE: Invalid message received: %s', message)
-        except SupervisorFault as fault:
-            message['data']['error'] = fault.faultString
-            message['data']['log'] = self.processmanager.read_log(message['data']['process_name'])
-            return message

lib/tfw/components/terminal_commands.py

@@ -3,6 +3,7 @@
 
 from abc import ABC
 from re import match
+from shlex import split
 
 from tfw.config.logs import logging
 
@@ -57,10 +58,10 @@ class TerminalCommands(ABC):
         return match(self._command_method_regex, string)
 
     def callback(self, history):
-        parts = history[-1].split()
+        parts = split(history[-1])
         command = parts[0]
         if command in self.command_implemetations.keys():
             try:
                 self.command_implemetations[command](*parts[1:])
-            except IndexError:
-                LOG.debug('Command "%s" failed!', command)
+            except Exception: # pylint: disable=broad-except
+                LOG.exception('Command "%s" failed:', command)

lib/tfw/linear_fsm.py

@@ -5,14 +5,18 @@ from .fsm_base import FSMBase
 
 
 class LinearFSM(FSMBase):
+    # pylint: disable=anomalous-backslash-in-string
     """
     This is a state machine for challenges with linear progression, consisting of
-    a number of steps specified in the constructor. It automatically sets up a single
-    action between states as such:
-    0 ==step_1==> 1 ==step_2==> 2 ==step_3==> 3 ... and so on
+    a number of steps specified in the constructor. It automatically sets up 2
+    actions (triggers) between states as such:
+    (0) --  step_1  --> (1) --  step_2  --> (2) --  step_3  --> (3) ... and so on
+        \-step_next-/       \-step_next-/       \-step_next-/
     """
     def __init__(self, number_of_steps):
         self.states = list(map(str, range(number_of_steps)))
-        self.transitions = [{'trigger': f'step_{int(index)+1}', 'source': index, 'dest': str(int(index)+1)}
-                            for index in self.states[:-1]]
+        self.transitions = []
+        for index in self.states[:-1]:
+            self.transitions.append({'trigger': f'step_{int(index)+1}', 'source': index, 'dest': str(int(index)+1)})
+            self.transitions.append({'trigger': 'step_next', 'source': index, 'dest': str(int(index)+1)})
         super(LinearFSM, self).__init__()

lib/tfw/mixins/__init__.py

@@ -1,7 +1,7 @@
 # Copyright (C) 2018 Avatao.com Innovative Learning Kft.
 # All Rights Reserved. See LICENSE file for details.
 
-from .supervisor_mixin import SupervisorMixin
+from .supervisor_mixin import SupervisorMixin, SupervisorLogMixin
 from .callback_mixin import CallbackMixin
 from .observer_mixin import ObserverMixin
 from .monitor_manager_mixin import MonitorManagerMixin

lib/tfw/mixins/monitor_manager_mixin.py

@@ -7,21 +7,24 @@ LOG = logging.getLogger(__name__)
 
 
 class MonitorManagerMixin:
-    def __init__(self, monitor_type, directory):
+    def __init__(self, monitor_type, *monitor_args):
         self._monitor_type = monitor_type
         self._monitor = None
-        self._monitored_directory = directory
+        self.monitor_args = monitor_args
         self.reload_monitor()
 
     @property
     def monitor(self):
         return self._monitor
 
+    def set_monitor_args(self, *monitor_args):
+        self.monitor_args = monitor_args
+
     def reload_monitor(self):
         if self._monitor:
             try:
                 self._monitor.stop()
             except KeyError:
                 LOG.debug('Working directory was removed – ignoring...')
-        self._monitor = self._monitor_type(self._monitored_directory)
+        self._monitor = self._monitor_type(*self.monitor_args)
         self._monitor.watch()   # This runs on a separate thread

lib/tfw/mixins/supervisor_mixin.py

@@ -9,9 +9,21 @@ from os import remove
 from tfw.config import TFWENV
 
 
-class SupervisorMixin:
-    supervisor = xmlrpc.client.ServerProxy(TFWENV.SUPERVISOR_HTTP_URI).supervisor
+def get_supervisor_instance():
+    return xmlrpc.client.ServerProxy(TFWENV.SUPERVISOR_HTTP_URI).supervisor
 
+
+class SupervisorBaseMixin:
+    supervisor = get_supervisor_instance()
+
+    def acquire_own_supervisor_instance(self):
+        """
+        Give this instance non-static, local xmlrpc client
+        """
+        self.supervisor = get_supervisor_instance()
+
+
+class SupervisorMixin(SupervisorBaseMixin):
     def stop_process(self, process_name):
         with suppress(SupervisorFault):
             self.supervisor.stopProcess(process_name)
@@ -19,12 +31,20 @@ class SupervisorMixin:
     def start_process(self, process_name):
         self.supervisor.startProcess(process_name)
 
-    def read_log(self, process_name):
-        logs = self.supervisor.readProcessStderrLog(process_name, 0, 0)
-        remove(self.supervisor.getProcessInfo(process_name)['stderr_logfile'])
-        self.supervisor.clearProcessLogs(process_name)
-        return logs
-
     def restart_process(self, process_name):
         self.stop_process(process_name)
         self.start_process(process_name)
+
+
+class SupervisorLogMixin(SupervisorBaseMixin):
+    def read_stdout(self, process_name, tail=0):
+        return self.supervisor.readProcessStdoutLog(process_name, -tail, 0)
+
+    def read_stderr(self, process_name, tail=0):
+        return self.supervisor.readProcessStderrLog(process_name, -tail, 0)
+
+    def clear_logs(self, process_name):
+        for logfile in ('stdout_logfile', 'stderr_logfile'):
+            with suppress(FileNotFoundError):
+                remove(self.supervisor.getProcessInfo(process_name)[logfile])
+        self.supervisor.clearProcessLogs(process_name)

lib/tfw/networking/event_handlers/server_connector.py

@@ -35,6 +35,9 @@ class ServerUplinkConnector(ZMQConnectorBase):
     def send_to_eventhandler(self, message):
         """
         Send a message to an event handler.
+        This envelopes the desired message in the 'data' field of the message to
+        TFWServer, which will mirror it to event handlers.
+
         :param message: JSON message you want to send
         :param message['key']: key of event handler you want to address
         """
@@ -46,6 +49,7 @@ class ServerUplinkConnector(ZMQConnectorBase):
     def send(self, message):
         """
         Send a message to the TFW server
+
         :param message: JSON message you want to send
         """
         self._zmq_push_socket.send_multipart(serialize_tfw_msg(message))

lib/tfw/networking/serialization.py

@@ -29,10 +29,16 @@ def validate_message(message):
 
 
 def serialize_tfw_msg(message):
+    """
+    Create TFW multipart data from message dict
+    """
     return _serialize_all(message['key'], message)
 
 
 def deserialize_tfw_msg(*args):
+    """
+    Return message from TFW multipart data
+    """
     return _deserialize_all(*args)[1]
 
 
@@ -45,12 +51,20 @@ def _deserialize_all(*args):
 
 
 def _serialize_single(data):
+    """
+    Return input as bytes
+    (serialize input if it is JSON)
+    """
     if not isinstance(data, str):
         data = json.dumps(data)
     return _encode_if_needed(data)
 
 
 def _deserialize_single(data):
+    """
+    Try parsing input as JSON, return it as
+    string if parsing fails.
+    """
     try:
         return json.loads(data)
     except ValueError:
@@ -58,12 +72,20 @@ def _deserialize_single(data):
 
 
 def _encode_if_needed(value):
+    """
+    Return input as bytes
+    (encode if input is string)
+    """
     if isinstance(value, str):
         value = value.encode('utf-8')
     return value
 
 
 def _decode_if_needed(value):
+    """
+    Return input as string
+    (decode if input is bytes)
+    """
     if isinstance(value, (bytes, bytearray)):
         value = value.decode('utf-8')
     return value

nginx/default.conf

@@ -4,6 +4,7 @@ server {
     proxy_connect_timeout 7d;
     proxy_send_timeout 7d;
     proxy_read_timeout 7d;
+    absolute_redirect off;
 
     location = /ws {
         proxy_pass http://127.0.0.1:${TFW_WEB_PORT};

setup.py

@@ -0,0 +1,23 @@
+from os.path import dirname, realpath, join
+
+from setuptools import setup, find_packages
+
+
+here = dirname(realpath(__file__))
+
+with open(join(here, 'VERSION'), 'r') as ifile:
+    version = ifile.read().strip('\n')
+with open(join(here, 'requirements.txt'), 'r') as ifile:
+    requirements = ifile.read().splitlines()
+
+setup(name='tfw',
+      version=version,
+      description='Avatao tutorial-framework',
+      url='https://github.com/avatao-content/baseimage-tutorial-framework',
+      author='Avatao.com Innovative Learning Kft.',
+      author_email='support@avatao.com',
+      license='custom',
+      packages=find_packages('lib'),
+      package_dir={'': 'lib'},
+      install_requires=requirements,
+      zip_safe=False)

supervisor/supervisord.conf

@@ -1,6 +1,7 @@
 [supervisord]
 user=root
-logfile = /tmp/supervisord.log
+logfile=/dev/null
+logfile_maxbytes=0
 loglevel = debug
 pidfile = /tmp/supervisord.pid